Nightmare Stalker is the older dragon while Dream Weaver is the younger.

While Gem was lost in the ''Caverns of Impossibilities'', He came across two entities that glowed a certain color in which Gem learned one was for nightmares and the other was for dreams.

They took the form that Gem imagined for them and they talked for a short bit. Shortly after Gem got out of the caverns, Night and Dream, nicknamed, enjoyed the forms that were imagined and caused the entrance of the caverns to appear in the Sythian Forrest in a certain location.